Existing electronic door locks are used to provide access to a building or facility, or to different locations within a building or facility. Such door locks provide an entrance to a room in response to mechanical or electrical actuation of a bolt extending from a door which engages a receiving portion of a door frame. Electronic door locks can be isolated individual devices or can be found in an electronic lock system which provides electronic communication between the electronic lock and a control system.
Some electronic lock systems are hardwired to an interface device which monitors and controls a state of the electronic lock. Other electronic lock systems include wireless electronic locks that communicate with a wireless interface device, also known as a panel interface module, sufficiently proximate to the electronic locks to enable wireless communication. The interface device is configured to monitor and control the state of a predetermined number of electronic locks such that multiple interfaced devices can be included in a facility of a large size since one interface device can be insufficient to monitor and control all of the electronic locks in the facility. Consequently, a number of interface devices are hardwired to a central controller, sometimes known as an access control panel, and are connected to the computer system of the facility. In some facilities, more than one access control panel can be required. The computer system provides updates to the electronic locks through the communication network.
Unlike a mechanical lock which requires a key to lock and unlock a door, electronic door locks can include a keypad or a card reader to enable a user to lock and unlock a door. The keypad or card reader can be located with the door lock which is located at the door, or the keypad or reader can be separated a distance from the door lock, such as at the interface device which is placed at a location accessible to the user. Even when a door lock includes a card reader, the door lock often includes a keypad in case the card reader malfunctions or for manual programming inputs.
Keypads include a plurality of buttons located on a panel which include alphanumeric characters such as, for example, numbers, digits, alphabetical letters, and/or symbols. The buttons, in different embodiments, include physical mechanical buttons, touch sensitive buttons, and capacitive buttons. Such buttons can be embodied as hardware or as software generated buttons appearing on a screen.
Keypad buttons can often be accessed at any time of the day or night, and consequently sometimes need to be illuminated. In some embodiments, the buttons are illuminated by a source of light which illuminates an external surface of the buttons. In other embodiments, the buttons are illuminated from behind. The incorporation of electronic code entry with mechanically structured door locks has typically been limited to mimicking the appearance of a smart phone with a dark glass-like face having numbers that appear when code entry is required after being activated. Silicone rubber style keypads are also used for the other electronic keypad locks and can appear on lower priced electronic lock products. Other keypads for an access door lock include buttons that use a black field which is hidden until being pressed, at which time the graphics illustrating the alphanumeric characters are illuminated.
Since a wide variety of environmental conditions exists, it is important that the buttons are legible under all lighting situations. However, currently available keypads do not provide legible characters during all types of environmental conditions. What is needed, therefore, is an electronic door lock system having alphanumeric characters which are readily seen and discerned by a user during a wide range of lighting conditions.